The present invention relates to railway hot box detectors; and more specifically, to a railway hot box detector calibration device.
Prior art hot box detector calibrators employ a black body heat source and a rotating wheel having an aperture therein. When the heat source, aperture and hot box detector are in alignment, infrared energy is transmitted directly from the hot box detector calibrator to the hot box detector and when the heat source, aperture and hot box detector are not in alignment, the wheel blocks the direct transmission of infrared (IR) energy to the detector. In this manner, an infrared energy difference (delta) is created as the wheel rotates and the wheel either allows energy to pass through the aperture or the wheel blocks the energy source. It is the precision in determining this difference in energy that is critical in calibrating the hot box detector. However, a problem exists in prior art hot box detector calibrators in that most hot box detector calibrators calculate the delta by assuming that the energy transmitted by the wheel is either a constant value or merely sense the temperature of the environment assume the wheel is at the same temperature as the environment. Therefore, the reference value of the infrared energy delta is an assumed rather than sensed value. As such, prior art hot box detector calibrators cannot provide the high level of precision or accuracy in their delta values required for proper calibration.